The interrupter of leakage protective device is conventional electrical equipment having mainly an electromagnetic breaker or a general breaker without sufficient interrupting capacity. When the leakage current in an electrical equipment is detected by means of a Zero Current Transformer (Z.C.T.), the said leakage current is amplified by an electronic device and further energizing the coil of an attached relay to open the contacts of said relay. Than the magnetic coil of the said magnetic switch is deenergized and the main contacts can be opened by virtue of the spring element in the magnetic switch, the power source thus being cut off. This electromagnetic switch can only open the load current in the electric equipment, when a short circuit malfunction occurs, its current reaches a very high, several hundred amperes for instance, which is beyond the interrupting capacity of a conventional electromagnetic switch. Therefore a no-fuse breaker with sufficient interrupting capacity is needed to be installed before the electromagnetic switch as the interrupter for protecting the circuit, the power source and leakage protective device; otherwise, the electromagnetic switch will be burned up when a short circuit malfunction takes place. However, installing a no-fuse breaker not only increases the cost but also involves a large installation.
Furthermore, an A.C. source is normally used by conventional electromagnetic switch, it is easy to get hot and produce loud noises. As the voltage approximates a sine wave of A.C., the main contacts are usually moved creepingly and in an unstable manner. That is the biggest defect.